Spring suspension



James; 1939.

K. RABE SPRING SUSPENSION Fil ed Oct. 12, 1934 54/ I //l /I/ I Patented June 6, 1939 g OFFICE sramo sosmsroiw ,Kari at... Stuttgart,

,asslgnortoDr.

, Germany ing. 1:. c. I. Porsche, K.-G., Stuttgart-Znffen- 'hausen, Germany, a company of Germany 12, 1934, Serial No. 748,051 In Germany October 18, 1933 a (01. sow-s1) --'I'his inventionrelates to an apparatus for regulating the tension of springs on power vehicles, and more particularly deals with the regulation of the tension of rotary springs mac- 5 cordance with the vehicle load.

An object of thisinvention is accordingly the provision of improved and novel means for regulating the tension of the springs of a vehicle.

A further object of this invention is the pro- 16 vision oi means for adjusting the abutments of rotary vehicle springs.

Another object of this invention is the provision of improved fluid pressure means for varying the tension of vehicle springs.

16 A stillfurther object of this invention is the provision of fluid pressure means responsive to the vehicle load for proportionately regulating the tension of the vehicle springs.

A specific object of this invention isthe pro 6 vision of a novel fiuid pressure system including a pump responsive to the vibrations of the vehicle for driving a piston for controlling the ten- Fig. 3 is a vertical section through the control cylinder, and

Fig. 4 is a vertical section through a modified.

pump piston, constructed as a shock absorber.

The swinging half-axles 2, 2' carrying the wheels I' are attached on to two pins or trimnions a 3, 8' on both sidesof the axle housing (not shown) which is preferably disposed in the longitudinal middle plane. The front of the pins 3, 3' are connected at I, I with spring rods l, l' preferably but not necessarily arranged co-axially with them. The front ends I, 'l' of the spring rods 6, i are connected with levers I, 8' and supported as abutments on the piston Ii by suitable means such as a lever arrangement 9, 8', which are guided in a common cylinder casing l secured on the frame. The rear of the pins 8, 3' are connected with the levers I 2, I! which are attached by means of a lever arrangement i3 II to the pistons l4, W of two pumps It, I! secured on the frame (Pig. 1 The cylinder cas- ;ing II is shown as divided by anintermediate in opposite directions.

wall I. into'two chambers l1, ii in which the pistons i I, I l, constructed as plungers, can move The outer end It of the piston I I is pressed by a spring it directly against the contact-surface of the lever I. In the middle position A ,the inner edge of the piston slides over apassage 2| in communication with an overfiow pipe 22 to a liquid reservoir II. Passages 24, 24 to which the pressure conduits 25, 25 of the pumps I5, I! are Joined (Fig. 3), communil0 cate with the inner sides of the cylinder chambers l1, l1.

The pump piston l4 guided in the housing I! is constructed as a plunger with a plate 26' on its upper end. A spring 2'1 placed on the hous- 1B ing ll maintains the piston 14 continuously in contact with the contact surface of the lever 12. In an extension at the lower end of the casing i5" is disposed a pressure valve 29 consisting of a ball and spring, which connects the pump chamber 20 with the pressure conduit 25. In the oppositely disposed extension ll of the housing ii there is disposed a suction valve 32 consisting of a ball and spring which connects the pump chamber with the suction conduit II. In the pressure con- 25 duit 2! is disposed a regulating air chamber 34 of known construction (Fig. 1).

The first adjustment of the spring suspension is efiected in the following'manner; first, the vehicle is-raised by any suitable means. In this 30 position the control valve I 1 assumes the middle position A and the pump piston l4, in consequence of the completely slackened spring, takes up the upper end position. The pump piston I4 is raised by the spring 21 on the abutment and in this way 35 fiuid is'suclred by the suction valve 32 into the pump chamber 30. Thereupon the lever 8 is moved outwardly in the direction of the arrow 0 until the inner edge 20 of the piston ll frees the passage 2|. Fluid from the collecting container 40 28 can now fiow through the conduit 22 into the cylinder chamber ii. The vehicle is now gradually lowered so that the wheels take up the load,

thereby I causing tightening of the springs.

Thereupon the piston ii is pressed inwards in the direction of the arrow P until the pressure in the regulating airv chamber 34 reaches equilibrium with the reaction of the support. Simultaneously the piston 14 moves downwards. in the direction of the arrow V whereby fiuid is forced through the pressure valve into the air chamber l4. The pressure in the air chamber 34 thereupon increases gradually until a certain preliminary tensioning of the springs is efiected which is suflicient for completely lowering the vehicle.

The automatic adjustment of the spring suspension is effected in the following way. As a result of the small preliminary tensioriing of the springs, the half axles 2, 2' ,are disposed in the incorrect position B" (negative set of the axle).

By the periodic vibrations of the wheels I, which are caused during travel over obstacles. and which gradually die out, the pump 15 now' conveys fluid into the air regulator 34. Each movement of the wheels I in the direction of the arrow S corresponds in this connection to a working stroke of the pump piston in the direction of the arrow V. Thus the pressure in the air chamber 34 gradually increases and drives the piston ll outwards in the direction of the arrow 0. The spring 6 is thereupon further tightened, the vehicle is raised, and the position of the axle 2 altered in the direction of the arrow T in the correct way. This step lasts until the inner edge 26 of the piston ll slides over the passage 2|, thereby releasing the fluid to the passage 22, and in effect acting as. a short-circuit. If the pump I5 is still working the piston ll nevertheless cannot be further moved, and the'pre-tensioning of the spring 6 cannot be increased. The axle 2 remains, therefore, in its correct position (normal set of the wheels) corresponding to the middle position A". If new the wheels swing in this position of the axles the piston ll acts as an oil brake, that is as a flxedabutment, If on the contrary the load on the vehicle increases, the piston II is again driven inwards, thepassage 2| is again obturated, and the procedure described can begin again.

The vibrations of the wheels are-effectively damped by the pumps IS, IS. In order to increase this action the piston ll can also be constructed as a shock-absorber piston. It incorporates in this case a pressure valve 35 and a suction valve 36 which are adjustable by screws.

If the piston ll moves downwards in the direction of the arrow V a part of the fluid from the pump chamber 30 is conveyed through the passage 40 into the pressure conduit 25 and simultaneously another part through the passage 49 into the chamber 43 over the piston ll. If,

however, the piston It moves upwards in the direction of the arrow vU, fluid is sucked partly over the passage ll from the chamber 43 and partly over the passage 42 from the suction conduit' 33 into the pump chamber ill. The greater the pressure in the air regulator, the more loaded, therefore, is the pressure valve 29, and all the more does the pressure valve 35 come into ac-.'

tion and the shock absorbing action become correspondingly emphasized. The construction described concerns an inversely acting shock absorber because the upward and not the downward movement of the wheels is damped; it is to be understood, however, that the inverse arrangement is possible.

In order, to adjust the correct mutual position of the half axles 2, 2 the air regulator pressure on both sides of-the vehicle must be maintained equally high. To this end the pressure conduits 25, 2 6 can be in communication through suitable over-pressure and compensating valves which act in such a way that during varying air regulator pressures-a part of the fluid flows from one conduit into the other. The cross sections of these over-pressure and compensating valves need be only extremely small in order to bring about the pressure compensation gradually, that is with great delay. Since on manufacturing grounds completely similar springs for both sides of the vehicle can not be readily procured, it is preferable to provide the air chambers 34, (with adlusting devices which adjust the correct mutual position of the half axles from the outset. The over-pressure and compensating valves are in this case used only as safety valves.

It will accordingly be seen that by the use of my invention it is possible to adjust the tension the most favorable mountingof the pump and of the control cylinder, independently of the construction of the frame. 1

The word frame as herein-used, is not to be understood as limited to such a device when formed separate from the body and coachwork of the vehicle, but as. including such devices when formed integral with said body or coach work.

The invention is not limited to the above constructional examples. Instead of a mechanical conveying pump driven bythe periodic. movements of the wheels an automatically acting pump can also be used, which for-example is constructed as a weight pump or spring weighted pump and is; directly driven by theoscillating movements of the chassis. This pump must naturally, since its driving energy is smaller, be of correspondingly greater dimensions. The adjustment proceeds in a completely similar manner.

While I have herein shown and described only certain'embodiments of certain features of my present invention, it is to be understood that they are to beregarded merely as illustrative and that I do not intend to limit myself and to expect as may be required by the claims which follow.

I claim:

1. In a vehicle, a body frame, a road wheel, a support for said road wheel and spring means connected at one end to said road wheel support and coacting at the other end with an abutment on said frame, and liquid pressure means interconnecting said abutment and frame for varying the relationshipbetween said spring and said abutment.

2. In a vehicle, a body frame, a road wheel, a support for said road wheel and spring means connected at one .end to said road wheel support and coacting at the other'nd with an abutment on said frame, and liquid pressure means interconnecting said abutment and frame for automatically varying the relationship between said spring and said abutment in accordance with the load carried by said vehicle.

3. In a vehicle, a body frame, a road wheel, a support for said road wheel and spring means connected at one end to said roadwheel support and coacting. at-the other end with an abutment on said frame and liquid pressure means for automatically varying the relationship between said spring and said abutment in accord- 5 a'nce with the load carried by said vehicle, said means being controlled by pump means connected between said frame and said wheel support.

4. Apparatus in accordance with claim 3 in w which the pump means is also a means for damo pening the vibrating movements of the road wheel support.

5. In a vehicle, a body frame, a road wheel, a support for said road wheel and spring means connected at one end to said road wheel support 5 and coacting at the other end with an abutment on said frame and liquid pressure means for automatically varying the relationship between said spring and said abutment in accordance with the load carried by said vehicle, said means being controlled by pump means connected between said frame and said wheel support and conduits extending from said pump means to said abutment varying means. v

6. In avehicle, a body frame, a road wheel, a ,5 supportfor said road wheel and spring means connected at one end to said roadwheel support and coacting at theother end with an abutment on said frame and fluid pressure means for automatically varying the relationship between said spring and said abutment in accordance withthe l'oad carried by said vehicle, said means being controlled by pump means connected between said frame and said wheel support and fluid conduits extending from said pump L means to said abutment varying means and' means for controlling the pressure in said conduits.

7. In a vehicle, a body frame, a plurality of road wheels, supports for each of said road 9 wheels, and spring means for each of said supports connected at one end to its respective road wheel support and coacting at the other end with an abutment carried by said frame, fluid pressure actuated means for varying the position of I said abutment, pump means connected between said frame and each of said wheel supports and conduits connecting said pump means with their respective fluid pressure actuated means.

8. Apparatus in accordance-with claim '7 in g which a plurality of said conduits are connec by pressure equalizing conduits.

9. In a vehicle havin'g a frame, in combination, a wheel for said vehicle, means for pivotally connecting said .wheel to said frame, rotary spring meansjattached at one end to said frame and at its other end to said wheel for the resilient support oi'said vehicle, and a fluid pressure regulating means mounted on said frame andattached to one end of said rotary spring means for controlling the tension'of said spring.

10. The combination according toclaim 9, in combination with a second fluid pressure means 'mounted'on said frame and attached to the other end of said rotary spring means, whereby said two fluid pressure means form abutments for said spring. 11. '1'he combination according to claim 9, in

combination with.a pump interconnected with.

to the vibrations of said vehicle for actuating said pump. a a

12. In a vehicle having a frame, in combination, a wheel for said vehicle, means for pivotally connecting said wheel to said frame, a lever, rotary spring means attached at one end to said pivotal connecting means and at its other end to one end of said lever, a fluid pressure regulating device mounted on said frame and having a control piston connected to the other end of said lever, and a pump connected to said fluid pressure regulating device and supplying fluid thereto, said pump having a piston connected for actuation by said pivotal connecting means.

13. The combination according to claim 12 including a driving lever interconnecting the pump piston with the pivotally connecting means.

14. The combination according to claim 9 in which said fluid pressure regulating means comprises a cylinder having a piston and an outlet in said cylinder adapted to be opened in a predetermined position of said piston, in combination with a pump, a first conduit interconnecting the pressure side of said pump with the inlet of said fluid pressure regulating means, and a second conduit interconnecting the inlet of said pump with the opening in said cylinder, whereby said fluid pressure means is short-circuited in said predetermined position of said piston.

15. The combination according to claim 9, in combination with means for dampening the movement of said spring means and wheel, said dampening means comprising a pump havinga piston connected to supply fluid to said fluid pressure means. 1

16. In a vehicle having a frame, in combination, a pair of wheels for said vehicle, means for pivotally connecting each of said wheels to said frame, a pair of springs, each attached at one end to said frame and at its other end to one of said wheels for the resilient supporting of said vehicle, a pair of fluid pressure regulating devices mounted on said frame and each attached to one end of one of said springs for controlling the tension thereof, a pairof conduits respectively connected to each of said fluid pressure devices for supplyingfluid to the same, regulating air chambers in each of said conduits, and valve means interconnecting said conduits for maintaining the pressures in each substantially identical.

19. The combination according to claim 9 in 

